抄録
Recently, research onto the hydraulics of stepped chutes was driven by needs for better design guidelines (OHTSU and YASUDA 1997, CHANSON and TOOMBES 2002, BOES and HAGER 2003). Although stepped channel flows are characterized by intense turbulence and strong flow aeration, most studies did not investigate the turbulence characteristics. In this study, mean velocity and turbulent intensity distributions for skimming flows have been investigated. The air-concentration ratio (void fraction), and the bubble count rate (the number of bubbles impacting the probe tip per second) have also been studied. The difference of velocity characteristics between the aerated and the non-aerated flow regions can be found. Further, the friction factor in aerated flow region can be obtained on the basis of the measurement of the air-concentration.
